AGETCULTUEE AND DENDEOLOGY. 
23 
we assumed in our calculation a high rate (15 °/ 0 ) of 
action of the phosphates, both as regards those contained 
in the night-soil and those given as additional manure. In 
the present exhausted condition of Japanese soils it will be 
most advisable not to apply too small proportions of phos¬ 
phates (fermented hones, superphosphates), but rather to 
approach as near as possible to the standards given by P. 
Wagner 1 ' who recommends that a general manure should 
contain for every 100 parts of nitrogen 
for the cultivation of cereals.. .200 p. of phosphoric acid and 
200 ,, ,, potash, 
„ „ „ „ beets 2 ' ...200 ,, „ phosphoric acid, 
j> » >> >> potatoes 160 ,, ,, ,, ,, 
Compared with the above, there exist in the fermented 
night-soil for every 100 p. of nitrogen only about. 
25 ,, „ phosphoric acid and 
50 ,, ,, potash 
To secure a maximum produce of the manures applied, 
the plants must be enabled to take up for every part of 
nitrogen a corresponding quantity of phosphoric acid, and 
if liberally supplied with an easily assimilable form of nitro¬ 
genous food, they exhibit at the same time a great demand 
for phosphoric acid, without which nutrient the nitrogen 
taken up remains useless, or interferes with the production 
of grain. The ammoniacal compounds of the excreta are, 
indeed, very speedily consumed by the plants, especially in 
this country, where the warm climate greatly favours the 
conversion of the ammonia into nitric acid, the most suit¬ 
able and most soluble form of nitrogenous food. A liberal 
1) Important practical questions on the subject of manures, 1885, p. 
63-67. 
2) These crops have a remarkable capacity for appropriating the 
potash of the soil, and seem, as a rule, not to reqirire a direct supply with 
that nutrient, but derive more benefit from a surplus of potash manure 
given to the preceding crop. 
